praetorius



(No Model.) 4 Sheets-Sheet 1.

I G. PRAE'TORIUS'. Preparing Clay to obtainPorous and Slagged Bodies. Nd. 235,961. Patented Dec. 28,1880.

N.FETERS, FHOTO-Ll'iHOGRAFHER. WASHINGTONfD C l 1 4. A A: r y m. m M V 4 Sheets-Sheen (HolilodeL) G PRABTORIU'S. Preparing Clay to obtain Porous and S-lagged Bodies.

Patented Dec. 28,1880.

l/k 126 12 for @M NJEIERS, PNDTU-UTHOGRAPHE-R. WASHINGTON. II. C.

Preparing Clay to btain Porous and S1agge.d' Bodies.

Patented Dec. 28,1880.

Ill A llll , N; FITIERSv PNDTO-LITHOGRAFHER. WASHlNGTON. D. C.

various kinds of chemical treatment.

is not important.

slagged porous clay.

the vessel.

I UNITED STATES PATENT ()FFICE.

GEORG PRAETORIUS, OF BRESLAU, PRUSSIA, GERMANY.

PREPARING CLAY TO OBTAIN POROUSAND SLAGGED BODIES.

SPECIFICATION forming part of Letters Patent No. 235,961, dated December 28, 1880,

I Application filed May 20, 1880. (No model.) Patented in Belgium October 29, 1879.

To all whom it may concern Be it known that I, GEORG PRAETORIUS, of Breslau, Province of Silesia, Kingdom of Prussia, Empire of Germany, have invented 5 a new and useful Method of Preparing Clay for Porous Earthenware, of which the following is a specification.

My object is to prepare porous earthenware suitable for use in filtering, absorption, and To avoid injury by acids, I employ clay which is free from iron, lime, or any of their compounds, although, when the vessel is to be used for filtering only, the absence of these substances I next subject a quantity of powdered charcoal to the action of n1uriatic acid. I then add to a mass of the clay thirty-three and one-third per cent. ofv the charcoal thus treated, and knead the mixture 20 thoroughly. When the vessel is to be used 25 same proportion of Norwegian feldspar. This will insure a certain vitreous quality in the surface of the vessel and prevent it from being disfigured by accidental scratching. I then shape the vessel in any convenient man- 0 ner known to potters and workers in earthenware. I then burn orfire it, so as to harden it in shape, changing the soft clay to earthenware, employing a sufficient degree of heat to eliminate the charcoal and leave only the This last operation is effected in chills when the vessel is to be used for chemical purposes, and in an oven when the vessel is intended for filtering. In the former case the flame is not allowed to reach In the latter case charcoal is used as fuel, or else the vessel is covered with a coat of charcoal-dust and clay,whichis shaved off after burning.

When it is desired that certain parts of the vessel shall not be porous, those parts are made of ordinary clay and glazed, or a partial glazing of certain parts may be effected by dipping them into oil. L

The figures of my drawings represent numerous articles, vessels, and apparatus which may be made wholly or partly from clay thus prepared; but, as they illustrate some of the applications of my invention rather than the invention itself, a detailed description of these devices is unnecessary.

For filtering purposes I also employ small fragments of clay, treated as hereinbefore described, and acting in the well-known manner of small pieces or particles arranged in layers. Such fragments may also be prepared by plastering a mixture of clay and charcoal on fibrw ngmial, burning out the charcoal and fibrous material, and crushing the residue.

Instead of feldspar and floor-spar, kaolin or other suitable materials may be employed for giving a hard surface, as hereinbefore stated.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

The process of manufacturing porous earthenware, consisting, first, in subjecting powdered charcoal to the action of muriatic acid, then mixing the same, thus treated,with pure clay, then adding to the mixture about ten per cent. of fluor-spar and an equal amount of feldspar, then shaping the mixtureinto earthenware articles, and finally burning out the charcoal by heat derived from charcoal flame or flame which does not reach the earthenware, substantially as set forth.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

DR. GEORG PBAETORIUS.

Witnesses:

HERMANN KI'iHN,

HUGO NEUMANN. 

